Single phase and three phase electricity supplies: what are they and how to upgrade & downgrade - DIY tutorial series

  • 28 October 2020
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Single phase and three phase electricity supplies: what are they and how to upgrade & downgrade - DIY tutorial series
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Single phase and three phase electricity supplies - your guide


How to tell if you have a three phase meter

The process for upgrading your supply to three phase

  1. You will be identified as needing a 3-phase supply by an electrician, due to requiring a high capacity of electricity in your property. This is usually the result of an extension to the property with more lighting or other building work.
  2. The DNO will need to attend to upgrade your main fuse to 3-phase.
  3. We book a 3-phase meter exchange (we do not have 3-phase smart meters) for a 3-phase trained engineer to upgrade your meter at the cost of £325. More info on costs here.

The booking with us is a 20 working day appointment, and our engineer or engineer contractor SMS may contact you directly to change for another date once they receive the booking. An electrician may also be required to rewire your consumer unit once the new meter has been installed, as we won't do this.


The process for downgrading your supply to single phase

  1. For downgrading from 3-phase back to single phase, the DNO will need to attend and remove two of the fuses/downgrade the fuse carrier.
  2. Our engineer will exchange the meter after the DNO have attended. This is also booked as a 20 working day appointment at a cost of £325 as a 3-phase trained engineer will be needed to remove the existing three phase equipment. More info on costs here.
  3. An electrician will also be required to check that a single phase supply can cope with the property's demands, the same as they would if you were looking to upgrade. 


Smart meters and a three phase supply

We don't currently offer three phase for S1 or S2 meters. 


In order to get a smart meter with a 3-phase supply, you’d need to follow the advice above outlining how to downgrade this supply. Then when it’s single phase, you can book in your appointment here


We’ll update this topic to confirm when three phase smart meters are available. 


That’s it for our guide on single and three phase supplies. Missed anything? Let us know as a comment below!

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